UserControlCheckBox.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ASCOM.ST4Commander
{
    public partial class UserControlCheckBox : CheckBox
    {
        public UserControlCheckBox()
        {
            InitializeComponent();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            if (!Enabled)
            {
                using (CheckBox temp = new CheckBox())
                using (Bitmap bitmap = new Bitmap(Width, Height))
                {
                    // Copy the relevant properties
                    temp.BackColor = BackColor;
                    temp.ForeColor = System.Drawing.Color.DarkGray;
                    temp.AutoSize = AutoSize;
                    temp.Size = Size;
                    temp.Width += 50;
                    temp.Text = Text;

                    //temp.ForeColor = Color.Red;   // the new disabled color          

                    temp.DrawToBitmap(bitmap, temp.ClientRectangle);   // (1) draw the temporary label to a bitmap, and then

                    e.Graphics.DrawImage(bitmap, Point.Empty);    // (2) draw that bitmap instead of the label object
                }
            }
            else
            {
                base.OnPaint(e);
            }
        }
    }
}